U.S. patent application number 16/781476 was filed with the patent office on 2020-08-20 for motor operated valve.
The applicant listed for this patent is TGK CO., LTD.. Invention is credited to Michio MATSUMOTO, Youichi MIURA, Shinji SAEKI, Tomohiro YUASA.
Application Number | 20200263800 16/781476 |
Document ID | 20200263800 / US20200263800 |
Family ID | 1000004671011 |
Filed Date | 2020-08-20 |
Patent Application | download [pdf] |
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United States Patent
Application |
20200263800 |
Kind Code |
A1 |
MATSUMOTO; Michio ; et
al. |
August 20, 2020 |
MOTOR OPERATED VALVE
Abstract
A motor operated valve includes a feed screw mechanism and a
stopper mechanism. The feed screw mechanism includes a guiding part
including an external thread portion on an outer surface thereof,
and a guided part that is a cylindrical member constituting a
rotation shaft of a rotor, and including an internal thread
portion, which is engaged with the external thread portion, on an
inner surface thereof. The stopper mechanism includes a stopper
portion provided on the guided part, and a stopping face formed
integrally with the guiding part. When a valve element is driven by
the motor to move in a valve closing direction, the stopping face
stops the stopper portion to restrict the movement of the rotor in
the valve closing direction.
Inventors: |
MATSUMOTO; Michio; (Tokyo,
JP) ; SAEKI; Shinji; (Tokyo, JP) ; MIURA;
Youichi; (Tokyo, JP) ; YUASA; Tomohiro;
(Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TGK CO., LTD. |
Tokyo |
|
JP |
|
|
Family ID: |
1000004671011 |
Appl. No.: |
16/781476 |
Filed: |
February 4, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F16K 31/047 20130101;
F25B 2341/0653 20130101; F25B 41/062 20130101 |
International
Class: |
F16K 31/04 20060101
F16K031/04 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 2019 |
JP |
2019-024319 |
Jun 14, 2019 |
JP |
2019-111263 |
Claims
1. A motor operated valve comprising: a body including an inflow
port through which fluid is introduced from an upstream side, an
outflow port through which the fluid is delivered to a downstream
side, and a passage through which the inflow port and the outflow
port communicate with each other; a valve element to open and close
a valve section provided on the passage; a motor including a rotor
for driving the valve element in opening and closing directions of
the valve section; a feed screw mechanism to convert rotational
movement of the rotor into translational movement; and a stopper
mechanism to restrict the translational movement of the rotor,
wherein the feed screw mechanism includes: a guiding part mounted
vertically on the body, and including an external thread portion on
an outer surface thereof; and a guided part made of a cylindrical
member constituting a rotation shaft of the rotor, including an
internal thread portion on an inner surface thereof, and mounted
around and thus supported by the guiding part, the internal thread
portion being engaged with the external thread portion, the stopper
mechanism includes: a stopper portion provided on the guided part;
and a stopping face formed integrally with the guiding part, and
when the valve element is driven by the motor to move in a valve
closing direction, the stopping face stops the stopper portion to
restrict the movement of the rotor in the valve closing
direction.
2. The motor operated valve according to claim 1, wherein the
stopper portion sticks out from an open end portion of the guided
part in an axial direction of the rotor, and when the valve element
is driven by the motor to move in the valve closing direction, the
stopper portion is stopped by the stopping face in a rotating
direction of the rotor, so that the movement of the rotor in the
valve closing direction is restricted.
3. The motor operated valve according to claim 2, wherein the
guiding part is made of a metal material by cutting.
4. The motor operated valve according to claim 3, wherein a first
notch for phase management of the external thread portion is formed
on an outer surface of the guiding part at a position of the
stopping face.
5. The motor operated valve according to claim 4, wherein in a part
of a plane including the first notch and an axis of the guiding
part, the part including the first notch with respect to the axis,
a distance in the axial direction between the first notch and a
root of the external thread portion is an integer multiple of a
thread pitch.
6. The motor operated valve according to claim 4, wherein the
guided part is made of a metal material by cutting, the stopper
portion is formed integrally with the guided part, and a second
notch for phase management of the internal thread portion is formed
on an inner surface of the guided part at a position of a face
thereof coming in contact with the stopping face.
7. The motor operated valve according to claim 2, wherein the motor
includes a stator for driving the rotor in the opening and closing
directions of the valve section, and an area in which the rotor and
the stator face each other is maximum when the stopper portion is
stopped by the stopping face.
8. The motor operated valve according to claim 7, wherein the valve
element has a pressure receiving structure that receives a pressure
of the fluid in the valve closing direction when the valve section
is closed.
Description
CLAIM OF PRIORITY
[0001] This application claims priority to Japanese Patent
Application No. 2019-024319 filed on Feb. 14, 2019 and Japanese
Patent Application No. 2019-111263 filed on Jun. 14, 2019, which
are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
[0002] The present invention relates to a motor operated valve and,
in particular, to a structure of a stopper mechanism for
restricting translational movement of a rotor.
2. Description of the Related Art
[0003] An automotive air conditioner typically includes a
compressor, a condenser, an expander, an evaporator, and so forth
arranged in a refrigeration cycle. For the expander, a motor
operated expansion valve that enables accurate control of the valve
opening degree by means of a stepping motor as a drive unit has
been increasingly used. Such a motor operated expansion valve
includes a mechanism for causing a valve element supported by an
end of a shaft to touch and leave a valve seat formed on a body.
For the movement of touching and leaving the valve seat, a
technology of converting rotational movement of a rotor into
translational movement of the shaft by employing a feed screw
mechanism has been proposed.
[0004] The motor operated expansion valve includes a stopper
mechanism for restricting the translational movement of the shaft.
In related art, a motor operated expansion valve including a
stopper member that moves integrally with a rotation shaft of a
rotor and a stopper member formed on a body, which achieve a
stopper function by being brought into contact with each other in
the rotating direction of the rotor, is known (refer to Japanese
Patent Application Publication No. H10-047517, for example).
RELATED ART LIST
[0005] (1) Japanese Patent Application Publication No.
H10-047517
[0006] Note that high assembling accuracy is required in assembly
of a motor operated expansion valve. In a case where a stopper
member, which is a member separate from the body, is used for a
stopper portion as in Japanese Patent Application Publication No.
H10-047517, however, the relative position of the stopper portion
has to be considered in the assembly. Such a structure may thus
require complicated assembly.
SUMMARY OF THE INVENTION
[0007] The present invention has been made in view of the above,
and one object thereof is to improve the efficiency of assembly of
a motor operated valve.
[0008] An embodiment of the present invention is a motor operated
valve. The motor operated valve includes: a body including an
inflow port through which fluid is introduced from an upstream
side, an outflow port through which the fluid is delivered to a
downstream side, and a passage through which the inflow port and
the outflow port communicate with each other; a valve element to
open and close a valve section provided on the passage; a motor
including a rotor for driving the valve element in opening and
closing directions of the valve section; a feed screw mechanism to
convert rotational movement of the rotor into translational
movement; and a stopper mechanism to restrict the translational
movement of the rotor. The feed screw mechanism includes: a guiding
part mounted vertically on the body, and including an external
thread portion on an outer surface thereof; and a guided part made
of a cylindrical member constituting a rotation shaft of the rotor,
including an internal thread portion on an inner surface thereof,
and mounted around and thus supported by the guiding part, the
internal thread portion being engaged with the external thread
portion. The stopper mechanism includes: a stopper portion provided
on the guided part; and a stopping face formed integrally with the
guiding part. When the valve element is driven by the motor to move
in a valve closing direction, the stopping face stops the stopper
portion to restrict the movement of the rotor in the valve closing
direction.
[0009] According to the embodiment, the stopping face constituting
the stopper portion is formed integrally with the guiding part, the
need for a process of assembling the stopping face and the guiding
part is eliminated. This achieves a motor operated valve that is
improved in the efficiency of assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross-sectional view of a structure of a motor
operated valve according to a first embodiment;
[0011] FIG. 2 is a cross-sectional view illustrating an open state
of the motor operated valve;
[0012] FIGS. 3A to 3C are external views of a stopper member;
[0013] FIG. 4 is a partially enlarged view of the vicinity of the
stopper member when the stopper member is mounted on a rotation
shaft;
[0014] FIGS. 5A to 5D illustrate operation processes of the motor
operated valve in transition from a closed state to a fully open
state;
[0015] FIGS. 6A and 6B are transverse sectional views illustrating
the vicinity of the stopper member in a state in which a stopper
mechanism functions;
[0016] FIGS. 7A to 7C illustrate structures of a guiding member and
the rotation shaft;
[0017] FIGS. 8A and 8B illustrate a state in which a second stopper
portion is stopped by a second stopping face (when the valve is
closed);
[0018] FIGS. 9A and 9B illustrate a state in which the second
stopper portion has turned 150 degrees from the valve closed
state;
[0019] FIGS. 10A and 10B illustrate a state in which the second
stopper portion has turned 300 degrees from the valve closed
state;
[0020] FIGS. 11A and 11B are cross-sectional views of the vicinity
of a stopper member according to a comparative example in a case
where the stopper member is used in the motor operated valve;
[0021] FIGS. 12A and 12B are cross-sectional views of a motor
operated valve in a case where a stopper member according to a
second embodiment is used in the motor operated valve;
[0022] FIGS. 13A to 13C are external views of the stopper
member;
[0023] FIGS. 14A and 14B are perspective views of the vicinity of
the stopper member in a case where the stopper member is used in
the motor operated valve;
[0024] FIGS. 15A and 15B are transverse sectional views of the
vicinity of the stopper member in a state in which a stopper
mechanism functions;
[0025] FIGS. 16A and 16B are cross-sectional views of the vicinity
of a stopper member of a motor operated valve according to a third
embodiment;
[0026] FIGS. 17A to 17E illustrate processes of operation of
mounting a rotation shaft and a guiding member;
[0027] FIGS. 18A and 18B are cross-sectional views of the vicinity
of a stopper member of a motor operated valve according to a fourth
embodiment;
[0028] FIGS. 19A to 19C are partially-enlarged cross-sectional
views of the vicinity of a stopper mechanism of a motor operated
valve according to a fifth embodiment; and
[0029] FIGS. 20A to 20C are conceptual diagrams illustrating
processes of formation of a stopper portion.
DETAILED DESCRIPTION
[0030] Certain embodiments of the invention will now be described.
The description is not intended to limit the scope of the present
invention, but to exemplify the invention.
[0031] The embodiments of the present invention will now be
described in detail with reference to the drawings. In the
description below, for convenience of description, the positional
relationship in each structure may be expressed with reference to
how the structure is depicted in the drawings. In the following
embodiments and modifications thereof, components that are
substantially the same will be designated by the same reference
numerals and redundant description thereof may be omitted as
appropriate.
First Embodiment
[0032] FIG. 1 is a cross-sectional view of a structure of a motor
operated valve 100 according to a first embodiment.
[0033] The motor operated valve 100 according to the present
embodiment is a motor operated expansion valve that functions as an
expander, and is constituted by an assembly of a body 200 and a
motor unit 300. A valve section 202 is provided inside the body
200.
[0034] An inlet port 222 through which high-temperature and
high-pressure fluid is introduced from the condenser side and an
outlet port 224 through which low-temperature and low-pressure
fluid throttled and expanded by the valve section 202 is delivered
toward the evaporator are formed at lateral sides of the body
200.
[0035] The body 200 includes a first body 220 having a bottomed
cylindrical shape, a second body 240 having a cylindrical shape,
and a third body 260 having a cylindrical shape. The second body
240 is mounted in an upper part of the first body 220. The third
body 260 is mounted in a lower part of the second body 240. The
third body 260 is located inside the first body 220. The valve
section 202 is accommodated inside the third body 260. A guiding
member 242 (guiding part) is mounted vertically at the center of an
upper part of the second body 240. The guiding member 242 is a
component made of a metal material by cutting, and has an external
thread portion 244 formed on the outer surface of a middle portion
in the axial direction of the guiding member 242. A lower end
portion of the guiding member 242 has a large diameter, and this
large-diameter portion 245 is fixed coaxially to the center of an
upper part of the second body 240. A shaft 246 extending from a
rotor 320 of the motor unit 300 is inserted in the inner side of
the second body 240. A lower end portion of the shaft 246 also
serves as a valve element 204 of the valve section 202. The guiding
member 242 slidably supports the shaft 246 in the axial direction
by the inner surface thereof, and rotatably and slidably supports a
rotation shaft 326 (guided part) of the rotor 320 by the outer
surface thereof.
[0036] The inlet port 222 is formed on one lateral side of the
first body 220, and the outlet port 224 is formed on another
lateral side thereof. Fluid is introduced through the inlet port
222, and delivered out through the outlet port 224. The inlet port
222 and the outlet port 224 communicate with each other via an
internal passage formed in the third body 260.
[0037] An inflow port 262 is formed at a lateral side of the third
body 260, and an outflow port 264 is formed at the bottom thereof.
The inflow port 262 communicates with the inlet port 222, and the
outflow port 264 communicates with the outlet port 224. The inflow
port 262 and the outflow port 264 communicate with each other via a
valve chamber 266. A valve hole 208 is formed inside the third body
260, and the upper end opening edge thereof serves as a valve seat
210. The valve element 204 moves toward and away from the valve
seat 210 to adjust the opening degree of the valve section 202.
[0038] In the valve chamber 266, an E-ring 212 is fitted to a lower
portion of the shaft 246. A spring support 214 is provided at an
upper position of the E-ring 212. A spring support 248 is also
provided under the guiding member 242. A spring 216 that biases the
valve element 204 in the closing direction of the valve section 202
is inserted between the two spring supports 214 and 248 coaxially
with the valve element 204. In the present embodiment, because the
lower end portion of the shaft 246 serves as the valve element 204,
the spring 216 also biases the shaft 246 in the valve closing
direction.
[0039] Next, a structure of the motor unit 300 will be
described.
[0040] The motor unit 300 is a three-phase stepping motor including
the rotor 320 and a stator 340. The motor unit 300 includes a can
302 having a bottomed cylindrical shape. The rotor 320 is located
inside the can 302, and the stator 340 is located outside of the
can 302.
[0041] The stator 340 includes a laminated core 342 and a bobbin
344. The laminated core 342 is constituted by disc-shaped cores
stacked in the axial direction. A coil 346 is wound around the
bobbin 344. The coil 346 and the bobbin 344 around which the coil
346 is wound constitute a "coil unit 345". The coil unit 345 is
mounted on the laminated core 342.
[0042] The stator 340 is integrated with a case 400 by molding. A
cap member 440 is fitted into an upper end opening of the case 400
in such a manner that a projection on a lower face of the cap
member 440 is inserted in the upper end opening of the case 400. A
printed circuit board 420 is mounted in a space S surrounded by the
case 400 and the cap member 440. The coil 346 is connected with the
printed circuit board 420. The case 400 includes a terminal cover
portion 402 that protects a terminal 422 for supplying power from
an external power supply to the printed circuit board 420.
[0043] Annular sealing members 206 and 201 are provided between the
third body 260 and the first body 220 and between the second body
240 and the first body 220, respectively. This structure prevents
leakage of fluid through a clearance between the first body 220 and
the third body 260 and a clearance between the second body 240 and
the first body 220. In addition, an annular sealing member 203 is
provided between the second body 240 and the case 400. This
structure prevents entry of external air (such as moisture) through
a clearance between the second body 240 and the case 400.
[0044] The rotor 320 includes a cylindrical rotor core 322, and a
magnet 324 around the outer circumference of the rotor core 322.
The rotor core 322 is mounted on the rotation shaft 326. The magnet
324 is magnetized with a plurality of poles in the circumferential
direction.
[0045] The rotation shaft 326 is made of a metal material by
cutting. The rotation shaft 326 is produced by integrally forming
the metal material into a bottomed cylindrical shape. The rotation
shaft 326 is mounted (outserted) around the guiding member 242 with
its open end facing downward. An internal thread portion 328 formed
on the inner surface of the rotation shaft 326 engages with the
external thread portion 244 of the guiding member 242. A feed screw
mechanism constituted by the thread portions converts the
rotational movement of the rotor 320 into the translational
movement in the axial direction. The engagement of the internal
thread portion 328 and the external thread portion 244 of the feed
screw mechanism will be referred to as a "screwed portion". Details
of the structure around the open end of the rotation shaft 326 will
be described later.
[0046] An upper portion of the shaft 246 is reduced in diameter,
and this diameter-reduced portion extends through the bottom of the
rotation shaft 326. An annular stopper 330 is fixed to the leading
end of the diameter-reduced portion. A back spring 332 that biases
the shaft 246 downward (valve closing direction) is provided
between the base end of the diameter-reduced portion and the bottom
of the rotation shaft 326. With this structure, while the valve
section 202 is being opened, the shaft 246 is moved integrally with
the rotor 320 in a state in which the stopper 330 is stopped by the
bottom of the rotation shaft 326. In contrast, while the valve
section 202 is being closed, the back spring 332 is compressed by
reaction force that the valve element 204 receives from the valve
seat 210. In this process, elastic reaction force of the back
spring 332 presses the valve element 204 against the valve seat
210, which increases the seating performance (valve closing
performance) of the valve element 204.
[0047] FIG. 2 is a cross-sectional view illustrating a fully open
state of the motor operated valve 100.
[0048] The motor operated valve 100 includes a stopper mechanism
that restricts the translational movement of the rotation shaft
326. The stopper mechanism includes a projection at the open end of
the rotation shaft 326, two projections on the outer surface of the
guiding member 242, and a stopper member 500.
[0049] The rotation shaft 326 has an enlarged-diameter portion 334,
which is increased in inner diameter, at a lower part thereof. The
enlarged-diameter portion 334 extends from immediately under the
internal thread portion 328 to the lower end of the rotation shaft
326. The open end of the rotation shaft 326 protrudes below the
rotor 320, and an annular recess 336 is formed along the outer
surface of the protruding portion. The stopper member 500 is fitted
into the recess 336.
[0050] A first projection 250 is formed on the outer surface of the
guiding member 242 at a position a little lower than the external
thread portion 244. A second projection 252 is formed at a position
lower than the first projection 250. The first projection 250
protrudes radially outward from the outer surface of the guiding
member 242. The height of the first projection 250 is set to be
lower than that of the second projection 252. In the first
embodiment, the second projection 252 corresponds to an upper end
portion of the large-diameter portion 245. The first projection 250
and the second projection 252 are formed integrally with the
guiding member 242. The first projection 250 defines the upper dead
center of the translational movement of the rotation shaft 326, and
the second projection 252 defines the lower dead center
thereof.
[0051] When the feed screw mechanism is driven by the motor unit
300 and the rotation shaft 326 starts moving upward, the shaft 246
is moved integrally with the rotor 320. As a result of this
movement, the valve element 204 leaves the valve seat 210. Thus,
fluid introduced through the inlet port 222, the inflow port 262,
and the valve chamber 266 flows out passing through the outflow
port 264 and the outlet port 224 in this order.
[0052] As illustrated in FIG. 1, in the valve closed state, part of
the open end of the rotation shaft 326 is in contact with the upper
end portion of the large-diameter portion 245 (the second
projection 252 in FIG. 2). In contrast, as illustrated in FIG. 2,
in the fully open state, part of the stopper member 500 is in
contact with the first projection 250. These two contact states
restrict downward (valve closing direction) and upward (valve
opening direction) translational movements of the rotation shaft
326. The contact states will be described later in detail.
[0053] Next, a structure of the stopper member 500 will be
described.
[0054] FIGS. 3A to 3C are external views of the stopper member 500.
FIG. 3A is a side view, FIG. 3B is a bottom view, and FIG. 3C is a
perspective view.
[0055] The stopper member 500 is made of a spring material. The
stopper member 500 is produced by punching a plate material and
bending the resulting belt-like material into a clip-like shape.
The stopper member 500 includes arc-shaped fitting portions 502, a
connecting portion 504 having a U shape in plan view, and guiding
portions 505. The stopper member 500 is such that the fitting
portions 502 extend from the respective ends of the connecting
portion 504, and the guiding portions 505 extends from the ends of
the fitting portions 502 opposite to the sides of the connecting
portion 504. The stopper member 500 has a substantially symmetric
structure (except for a protrusion 508, which will be described
later) with respect to a bisector L of the connecting portion
504.
[0056] The fitting portions 502 are constituted by two arc-shaped
fitting members 503. The two fitting members 503 are arranged at
symmetric positions with respect to the bisector L. The two fitting
members 503 have an inscribed circle in common. The curvature of
the inscribed circle of the fitting portions 502 (the inscribed
circle of the fitting members 503) is equal to that of the bottom
of the recess 336. The guiding portions 505 are constituted by two
guiding members 507. These guiding members 507 have a shape
extending from the points of connection with the fitting members
503 in directions approaching each other, and then extending in
directions away from each other. The portions of the guiding
portions 505 where the distance between the two guiding members 507
is shortest (the portions where the extending directions changes
from the directions approaching each other to the directions away
from each other) will be referred to as "narrow portions N".
[0057] The stopper member 500 further includes a sticking out
portion 506. The sticking out portion 506 has an L shape in side
view, sticks out downward from the connecting portion 504 and then
extends toward the center axis of the inscribed circle of the
fitting portions 502. The extending direction of the sticking out
portion 506 is coincident with the extending direction of the
bisector L. The sticking out portion 506 has a tapered distal end.
In addition, the end face of the distal end of the sticking out
portion 506 has a curvature. The sticking out portion 506 includes
the protrusion 508 on a side face of the distal end. The protrusion
508 extends from the sticking out portion 506 in the
circumferential direction.
[0058] FIG. 4 is a partially enlarged view of the vicinity of the
stopper member 500 when the stopper member 500 is mounted on the
rotation shaft 326.
[0059] The lower end of the rotation shaft 326 has a stepped shape.
The stepped shape includes a stepped portion 338 and a projection
327. The stepped portion 338 is recessed from the lower end face of
the rotation shaft 326. The stepped portion 338 extends in the
rotating direction of the rotation shaft 326 (the circumferential
direction of the rotation shaft 326). The sticking out portion 506
is inserted in the stepped portion 338 in the radial direction. The
sticking out portion 506 is movable within the range of the stepped
portion 338 in the rotating direction. The projection 327 protrudes
from the lower end face of the rotation shaft 326. The sticking out
portion 506 is positioned between the projection 327 and the first
projection 250. Thus, the portion of the projection 327 facing the
sticking out portion 506 functions as a "holding portion". In
addition, the portion of the projection 327 opposite to the holding
portion functions as a "stopping portion" coming into contact with
the second projection 252 (derails of which will be described
later).
[0060] The stopper member 500 is mounted on the rotation shaft 326
in a state in which the sticking out portion 506 is lower than the
fitting portions 502. The fitting portions 502 are fitted into the
recess 336.
[0061] A gap is present between the inner surface of the
enlarged-diameter portion 334 and the outer surface of the guiding
member 242. The distal end of the sticking out portion 506 is
positioned in the gap. Specifically, the sticking out portion 506
sticks out radially inward from the inner surface of the rotation
shaft 326. In addition, a clearance is formed between the distal
end face of the sticking out portion 506 and the outer surface of
the guiding member 242. The stopper member 500 is thus movable
around the guiding member 242 in the rotating direction of the
rotation shaft 326.
[0062] At some point during the translational movement of the
rotation shaft 326 (details of which will be described later), the
sticking out portion 506 is stopped by the first projection 250 in
the rotating direction of the rotation shaft 326. At this point,
the projection 327 (functioning as the "holding portion") is in
contact with the face of the sticking out portion 506 opposite to
the face thereof in contact with the first projection 250. The
projection 327 presses the sticking out portion 506 in the rotating
direction of the rotation shaft 326 to hold the sticking out
portion 506 between the projection 327 and the first projection
250.
[0063] The protrusion 508 is inserted between the inner surface of
the projection 327 and the outer surface of the guiding member 242.
In other words, the protrusion 508 is sandwiched in the radial
direction between the inner surface of the projection 327 and the
outer surface of the guiding member 242. This structure enables the
protrusion 508 to come in contact with the inner surface of the
projection 327 and stay on the inner side of the projection 327
even when the stopper member 500 has received a radially outward
force. This prevents the stopper member 500 from falling off the
rotation shaft 326. The protrusion 508 can also be referred to as a
"catching portion" for preventing the stopper member 500 from
falling off the rotation shaft 326.
[0064] A method of assembling the rotation shaft 326, the guiding
member 242, and the stopper member 500 will now be explained with
reference to FIG. 4.
[0065] First, the leading end of the guiding member 242 is inserted
into the rotation shaft 326. The external thread portion 244 and
the internal thread portion 328 are engaged with each other (see
FIG. 1), so that the guiding member 242 is inserted into the
rotation shaft 326. A gap is present between the first projection
250 and the enlarged-diameter portion 334. The presence of the gap
allows the first projection 250 to be inserted into the
enlarged-diameter portion 334. After the first projection 250 is
inserted to a position upper than the stepped portion 338, the
stopper member 500 is made to fit to the rotation shaft 326 in the
radial direction. In this process, the ends of the guiding portions
505 are first applied to the bottom of the recess 336, and the
guiding portions 505 and the fitting portions 502 are then fitted
along the recess 336. The narrow portions N of the guiding portions
505 are widened along the bottom of the recess 336 and pass over
the bottom. When the narrow portions N have passed over the bottom
of the recess 336, the widened narrow portions N are restored by
the spring force. When the fitting portions 502 are fitted to the
positions where the bottom of the recess 336 and the fitting
portions 502 are concentric, the fitting of the fitting portions
502 into the recess 336 is completed. The sticking out portion 506
is inserted into the stepped portion 338. The protrusion 508 is
inserted between the projection 327 and the guiding member 242, and
the sticking out portion 506 is held between the projection 327 and
the first projection 250. In this manner, the assembly of the
rotation shaft 326, the guiding member 242, and the stopper member
500 is completed.
[0066] For assembling the rotation shaft 326 and the guiding member
242, the first projection 250 needs to be inserted into the
rotation shaft 326. Thus, the inner diameter of the rotation shaft
326 (the inner diameter of the enlarged-diameter portion 334) is
set to be larger than the diameter of the circumscribed circle of
the first projection 250 with the center at the axis of the guiding
member 242. In addition, for restricting the upward (valve opening
direction) translational movement of the rotation shaft 326 by
using the first projection 250, the first projection 250 and the
rotation shaft 326 need to come in contact with each other at some
portion. In the present embodiment, after the rotation shaft 326
and the guiding member 242 are assembled and the first projection
250 is inserted into the rotation shaft 326, the stopper member 500
that functions as a stopper is mounted. The stopper sticks out
radially inward relative to the inner diameter of the rotation
shaft 326. This structure enables smooth assembly of the rotation
shaft 326 and the guiding member 242. In addition, the stopper
mechanism functions during valve opening operation. This improves
the efficiency of assembly of the motor operated valve 100
including the stopper mechanism.
[0067] In mounting the stopper member 500, the guiding portions 505
enable the fitting portions 502 to be smoothly fit into the recess
336. In addition, the tapered shape of the distal end of the
sticking out portion 506 enables the sticking out portion 506 to be
smoothly inserted into the stepped portion 338. Note that a notch
253 extends on the outer surface of the second projection 252 in
the circumferential direction. The notch 253 extends like a root of
a thread along a virtual spiral about the axis of the guiding
member 242. In addition, a notch 301 extends on the inner surface
of the projection 327 in the circumferential direction. The notch
301 extends like a root of a thread along a virtual spiral about
the axis of the rotation shaft 326. Details of the notch 253 and
the notch 301 will be described later.
[0068] FIGS. 5A to 5D illustrate operation processes of the motor
operated valve 100 in transition from the closed state to the fully
open state. FIG. 5A illustrates the valve closed state, FIG. 5B
illustrates a state slightly open from the closed state, FIG. 5C is
a state slightly closed from the fully open state, and FIG. 5D
illustrates the fully open state.
[0069] FIGS. 6A and 6B are transverse sectional views illustrating
the vicinity of the stopper member 500 in a state in which the
stopper mechanism functions as viewed from below. FIG. 6A
illustrates the valve closed state, and FIG. 6B illustrates the
fully open state.
[0070] Operation around the stopper member 500 will be
explained.
[0071] When the valve section 202 is in the closed state, the
relative positions of the rotation shaft 326, the guiding member
242, and the stopper member 500 are as illustrated in FIGS. 5A and
6A. Specifically, the second projection 252 and the projection 327
(functioning as a "stopping portion") are in contact with each
other in the rotating direction of the rotation shaft 326, so that
the downward movement of the rotation shaft 326 is restricted. In
the process in which the valve section 202 (see FIG. 1) is opened
(FIGS. 5B and 5C), the second projection 252 and the projection 327
are separated from each other, and the movement of the rotation
shaft 326 in the axial direction is permitted. When the valve
section 202 becomes fully open (FIGS. 5D and 6B), the first
projection 250 and the sticking out portion 506 come into contact
with each other, and the upward movement of the rotation shaft 326
is restricted. The projection 327 and the sticking out portion 506
move integrally during the translational movement of the rotation
shaft 326 from the valve closed state to the fully open state of
the valve section 202.
[0072] As illustrated in FIGS. 5D and 6B, the sticking out portion
506 is referred to as a "first stopper portion 820", and the face
of the first projection 250 coming in contact with the sticking out
portion 506 is referred to as a "first stopping face 830". A
stopper mechanism including the first stopper portion 820 and the
first stopping face 830 and restricting the upward movement of the
rotation shaft 326 is referred to as a "first stopper mechanism".
When the first stopping face 830 stops the first stopper portion
820, the movement of the rotation shaft 326 in the valve opening
direction is restricted. In addition, as illustrated in FIGS. 5A
and 6A, the projection 327 is referred to as a "second stopper
portion 800", and the face of the second projection 252 coming in
contact with the projection 327 is referred to as a "second
stopping face 810". A stopper mechanism including the second
stopper portion 800 and the second stopping face 810 and
restricting the downward movement of the rotation shaft 326 is
referred to as a "second stopper mechanism". When the second
stopping face 810 stops the second stopper portion 800, the
movement of the rotation shaft 326 in the valve closing direction
is restricted. In addition, as illustrated in FIG. 6A, the face of
second stopper portion 800 coming in contact with the second
stopping face 810 is referred to as a "contact face 812".
[0073] With reference back to FIG. 1, a pressure receiving
structure of the motor operated valve 100 will be described.
[0074] In the motor operated valve 100, fluid introduced through
the inlet port 222 is delivered into the can 302 via the inflow
port 262 and the valve chamber 266. The fluid introduced inside the
can 302 applies a downward pressure (the pressure of fluid upstream
of the valve section 202) to the upper end portion of the shaft
246. In the meantime, fluid introduced in the outlet port 224 and
the outflow port 264 applies an upward pressure (the pressure of
fluid downstream of the valve section 202) to the lower end portion
of the shaft 246 (the valve element 204). When the valve section
202 is closed, the pressure of the fluid upstream of the valve
section 202 is higher than that of the downstream fluid. Thus, in
the valve closed state, the shaft 246 (the valve element 204)
receives a force caused by pressure difference between the upstream
fluid pressure and the downstream fluid pressure in the valve
closing direction. The force biasing the shaft 246 in the valve
closing direction becomes maximum in the valve closed state, that
is, when the second stopping face 810 stops the second stopper
portion 800 (FIGS. 5A and 6A).
[0075] When the valve section 202 is opened from the closed state,
a force acting against the force caused by the pressure difference
and biasing the shaft 246 in the valve closing direction is needed.
As described in relation to FIG. 1, the translational movement of
the shaft 246 (the valve element 204) is obtained by conversion of
the rotational movement of the rotor 320 moving integrally
therewith. Thus, the thrust in the axial direction of the valve
element 204 is larger as the torque applied to the rotor 320 is
larger. The torque is proportional to an area in which the rotor
320 and the stator 340 face each other (an area in which the rotor
320 and the stator 340 overlap each other). In the present
embodiment, the rotor 320 and the stator 340 are set so that the
rotor 320 and the stator 340 are at the same height and the area in
which the rotor 320 and the stator 340 face each other is thus
maximum when the valve section 202 is closed, that is, when the
second stopping face 810 stops the second stopper portion 800. This
structure increases the thrust for lifting the valve element 204
upward.
[0076] Structures of the guiding member 242 and the rotation shaft
326 will now be described.
[0077] FIGS. 7A to 7C illustrate the structures of the guiding
member 242 and the rotation shaft 326. FIG. 7A is a cross-sectional
view including the second stopping face 810 of the guiding member
242, FIG. 7B is a cross-sectional view including the contact face
812 of the rotation shaft 326, and FIG. 7C is a conceptual diagram
illustrating a state of contact of second projection 252 and the
second stopper portion 800.
[0078] As described in relation to FIG. 4, the notch 253 in a
spiral shape similar to the external thread portion 244 is formed
on the outer surface of the second projection 252. In addition, the
notch 301 in a spiral shape similar to the internal thread portion
328 is formed on the inner surface of the projection 327.
[0079] The distance between adjacent roots of each of the external
thread portion 244 in FIG. 7A and the internal thread portion 328
in FIG. 7B is referred to a "pitch P". The cross-section
illustrated in FIG. 7A is present on a plane including an
intersection 253a of the deepest line of the notch 253 and the
second stopping face 810, and the axis C1 of the guiding member
242. In a part of the plane including the intersection 253a with
respect to the axis C1 (the left part of the cross-sectional view
of FIG. 7A), the distance L1 in the axial direction between the
notch 253 and the root of the external thread portion 244 is set to
a (a is an integer) times the pitch P. The cross-section
illustrated in FIG. 7B is present on a plane including an
intersection 301a of the deepest line of the notch 301 and the
contact face 812, and the axis C2 of the rotation shaft 326. In a
part of the plane including the intersection 301a with respect to
the axis C2 (the right part of the cross-sectional view of FIG.
7B), the distance L2 in the axial direction between the notch 301
and the root of the internal thread portion 328 is also set to be b
(b is an integer) times the pitch P. Note that a and b may either
be the same number or different numbers. The technical significance
of the distance L1 and the distance L2 will be described later with
the explanation of FIG. 7C.
[0080] Formation of the external thread portion 244 of the guiding
member 242 and the internal thread portion 328 of the rotation
shaft 326 will be described. As described in relation to FIG. 1,
the guiding member 242 is produced by cutting a columnar metal
material (hereinafter referred to as a "columnar member"). In
cutting of the guiding member 242, the first projection 250 and the
second projection 252 are formed on the outer surface of the
columnar member. The external thread portion 244 is formed by
moving a working tool in a direction approaching the second
projection 252 from a machining start position of the external
thread portion 244 while the columnar member is rotated about its
axis. After the formation of the external thread portion 244, the
rotation of the columnar member and the movement of the working
tool are maintained, and the notch 253 is formed on the outer
surface of the columnar member by using the working tool. As a
result, the distance L1 is an integer multiple of the pitch P.
[0081] The rotation shaft 326 is produced by cutting a cylindrical
metal material (hereinafter referred to as a "cylindrical member").
Before cutting of the internal thread portion 328, the notch 301 is
formed on the inner surface of the cylindrical member while
rotating the cylindrical member about its axis. The notch 301 is
formed by moving a working tool used for forming the internal
thread portion 328 in the axial direction. The rotation of the
cylindrical member and the movement of the working tool are
maintained, and the internal thread portion 328 is formed by moving
the working tool in the direction away from the notch 301. As a
result, the distance L2 is an integer multiple of the pitch P.
[0082] In the present embodiment, the second stopping face 810 and
the external thread portion 244 are formed integrally with the
guiding member 242. In addition, the second stopper portion 800 and
the internal thread portion 328 are formed integrally with the
rotation shaft 326. For the second stopping face 810 to stop the
second stopper portion 800, phase management of the second stopping
face 810 and the external thread portion 244, and phase management
of the contact face 812 and the internal thread portion 328 need to
be strictly performed, as will be described later.
[0083] FIGS. 8A and 8B illustrate a state in which the second
stopper portion 800 is stopped by the second stopping face 810
(when the valve is closed). FIG. 8A is a front view of the vicinity
of the notch 253, and FIG. 8B is a cross-sectional view along a
line shown by arrows A-A in FIG. 8A.
[0084] FIGS. 9A and 9B illustrate a state in which the rotation
shaft 326 has turned 150 degrees from the state illustrated in
FIGS. 8A and 8B. FIG. 9A is a front view of the vicinity of the
notch 253, and FIG. 9B is a cross-sectional view along a line shown
by arrows B-B in FIG. 9A.
[0085] FIGS. 10A and 10B illustrate a state in which the rotation
shaft 326 has turned 300 degrees from the state illustrated in
FIGS. 8A and 8B. FIG. 10A is a front view of the vicinity of the
notch 253, and FIG. 10B is a cross-sectional view along a line
shown by arrows C-C in FIG. 10A.
[0086] When the rotation shaft 326 turns in a direction
corresponding to valve opening operation from the valve closed
state, the second stopper portion 800 reaches the second projection
252 at some angle. In order to prevent the rotation of the rotation
shaft 326 from being blocked by the second stopper portion 800
hitting the second projection 252, the lower end face of the second
stopper portion 800 has to be located above the upper end face of
the second projection 252 at this angle. Thus, the length of
contact between the contact face 812 and the second stopping face
810 in the axial direction is set to be shorter than a translation
distance (pitch P) of the second stopper portion 800 while the
rotation shaft 326 makes one turn. This enables the second stopper
portion 800 to smoothly move without hitting the second projection
252 during the valve opening operation. In addition, in order that
the second stopper portion 800 is stably stopped by the second
stopping face 810 in the valve closed state, the area of contact
thereof needs to be as large as possible. Thus, the length of the
contact in the axial direction is set to be as close to the pitch P
as possible. This enables the second stopping face 810 to
appropriately stop the second stopper portion 800.
[0087] As illustrated in FIGS. 8A to 10B, the second projection 252
and the second stopper portion 800 each actually extend along a
virtual arc about the axis. Specifically, the second projection 252
and the second stopper portion 800 each extend on a virtual arc
having a center angle of 30 degrees. Thus, the length of contact
between the contact face 812 and the second stopping face 810 in
the axial direction is set to be shorter than the translation
distance of the second stopper portion 800 while the second stopper
portion 800 turns 300 degrees and also as long as possible. This
enables the second stopper portion 800 to avoid interference from
the second projection 252 during the valve opening operation, and
enables the second stopping face 810 to appropriately stop the
second stopper portion 800.
[0088] The relation between the length of contact between the
contact face 812 and the second stopping face 810 in the axial
direction and the pitch P is determined by the relative positions
of the second stopping face 810 and the external thread portion 244
(phases based on the rotation) and the relative positions of the
contact face 812 and the internal thread portion 328 (phases based
on the rotation). These phases will be explained next.
[0089] The distance L1 and the distance L2 will be explained with
reference back to FIGS. 7A to 7C.
[0090] FIG. 7C illustrates a state of contact between the second
projection 252 and the second stopper portion 800. In FIG. 7C,
various lengths of the second projection 252 and the second stopper
portion 800 are shown. l1 represents the distance in the axial
direction between the upper end face of the second projection 252
and the intersection 253a. l2 represents the distance in the axial
direction between the lower end face of the second stopper portion
800 and the intersection 301a. lm represents the distance in the
axial direction between the intersection 253a and the intersection
301a when the valve is closed.
[0091] As described in relation to FIGS. 8A to 10B, the length
l1+l2-lm of the contact between the contact face 812 and the second
stopping face 810 in the axial direction is set to be shorter than
the pitch P. This setting is based on a case where both of the
center angles of the virtual arcs along which the second stopper
portion 800 and the second projection 252 extend are 0 degrees. In
fact, as illustrated in FIGS. 8A to 10B, the second stopper portion
800 and the second projection 252 each have a length in the
rotating direction of the rotation shaft 326. With reference back
to FIG. 7C, when a total of the center angles of the virtual arcs
along which the second stopper portion 800 and the second
projection 252 extend is x degrees, a condition for the second
stopper portion 800 to smoothly rotate during the valve opening
operation is: l1+l2-lm<(1-x/360)P (formula 1).
[0092] As described in relation to FIGS. 7A and 7B, the distance L1
and the distance L2 are set to a times the pitch P and b times the
pitch P, respectively. In other words, both of the distance L1 and
the distance L2 are set to integer multiples of the pitch P. When
the external thread portion 244 and the internal thread portion 328
engage with each other, the crest of the external thread portion
244 faces the root of the internal thread portion 328. Thus, the
distance lm illustrated in FIG. 7C is 1/2P. In addition, the center
angle x is determined when the second stopper portion 800 and the
second projection 252 are designed. Thus, the remaining variables
in the formula 1 are the distance l1 and the distance l2.
[0093] Because the distance L1 and the distance L2 are both set to
be integer multiples of the pitch P, the distance lm is determined.
Thus, only the distance l1 and the distance l2 need to be set to
satisfy the formula 1. Because the distance l1 and the distance l2
are determined on the basis of the center angle x, phase management
is also needed accordingly. Because the distance L1 and the
distance L2 are both integer multiples of the pitch P, simpler
design of the second stopper portion 800 and the second projection
252 for achieving appropriate valve opening operation is
achieved.
[0094] As described above, according to the first embodiment, the
second projection 252 (the second stopping face 810) is formed
integrally with the guiding member 242. This structure eliminates
the need for assembling the second stopping face 810 and the
guiding member 242, which improves the efficiency of assembly of
the motor operated valve 100.
[0095] According to the first embodiment, the distance L1 and the
distance L2 are both integer multiples of the pitch P. This setting
enables appropriate contact between the contact face 812 and the
second stopping face 810, and achieves simpler design of the second
stopper portion 800 and the second projection 252 for smoothly
rotating the second stopper portion 800.
[0096] According to the first embodiment, the stopper member 500 is
mounted after the rotation shaft 326 and the guiding member 242 are
assembled. The inner diameter of the enlarged-diameter portion 334
is larger than the diameter of the circumscribed circle of the
first projection 250 with the center at the axis of the guiding
member 242. In addition, the enlarged-diameter portion 334 extends
to the lower end of the rotation shaft 326. As a result, the
rotation shaft 326 can be smoothly mounted around the guiding
member 242. In addition, the sticking out portion 506 sticks out
radially inward from the inner surface of the rotation shaft 326.
This enables the first projection 250 and the sticking out portion
506 to come into contact with each other in the rotating direction
of the rotation shaft 326 during the valve opening operation. Thus,
the translational movement in the valve opening direction of the
rotation shaft 326 can be restricted during the valve opening
operation.
[0097] According to the first embodiment, the first projection 250
is located inside the rotation shaft 326 in the valve closed
stated. In addition, in transition from the valve closed state to
the fully open state, the first projection 250 relatively moves in
the inside of the rotation shaft 326 to approach the lower end (the
open end) of the rotation shaft 326. In the fully open state, the
position of the first projection 250 is a position at which the
first projection 250 stops the sticking out portion 506. In other
words, at least part of the first stopping face 830 is contained
inside the enlarged-diameter portion 334 depending on the position
of the rotor 320 in the translation direction (the driving state of
the rotor 320). Because the first stopping face 830 is present
under the rotation shaft 326 of the rotor 320, the total length of
the rotor 320, the first stopper mechanism, and the second stopper
mechanism in the axial direction can be made shorter. Thus, the
length of the motor operated valve 100 in the axial direction can
be made shorter.
[0098] According to the first embodiment, the first stopping face
830 and the second stopping face 810 are located between the
screwed portion and the valve section 202. In addition, the screwed
portion of the feed screw mechanism and the rotor 320 are located
at the same height in the axial direction. Thus, the distance
between the center of gravity and the support point of the rotor
320 can be made shorter, and whirling of the rotor 320 due to the
rotation of the rotor 320 is suppressed.
[0099] FIGS. 11A and 11B are cross-sectional views of the vicinity
of a stopper member 600 according to a comparative example as
viewed from below in a case where the stopper member 600 is used in
the motor operated valve 100. FIG. 11A illustrates a state in which
the stopper member 600 is properly fitted to the rotation shaft
326. FIG. 11B illustrates a state in which the stopper member 600
is about to fall off the rotation shaft 326.
[0100] In FIGS. 11A and 11B, a solid arrow indicates the rotating
direction of the rotation shaft 326 during the valve opening
operation. A broken line arrow indicates the moving direction of
the stopper member 600.
[0101] The stopper member 600 does not include a part corresponding
to the protrusion 508 (see FIGS. 3A to 3C) of the stopper member
500 at the distal end portion of the sticking out portion 506. In
the fully open state, the sticking out portion 506 is stopped by
the first projection 250 in the rotating direction of the rotation
shaft 326. The projection 327 is in contact with the sticking out
portion 506 in a state in which the sticking out portion 506 is
sandwiched between the projection 327 and the first projection 250.
Even after the fully open state is reached, the rotation shaft 326
continues to turn in the rotating direction of the valve opening
operation (the direction indicated by the solid arrow in FIGS. 11A
and 11B) by the driving of the motor unit 300. The force of this
turning of the rotation shaft 326 acts as a force of the projection
327 pressing the sticking out portion 506 against the first
projection 250. The distal end portion of the sticking out portion
506 has a tapered shape. Thus, a force pressing the sticking out
portion 506 radially outward (in the direction indicated by the
broken line arrow in FIGS. 11A and 11B) is applied by the pressing
force from the projection 327 and the reaction force from the first
projection 250. This pressing force causes the stopper member 600
to fall off the rotation shaft 326. In a case where the spring
force of the stopper member 600 is large, however, the fitting
portions 502 can stay in the recess 336. In the case where the
spring force of the stopper member 600 is large, the catching
portion may not be provided like the stopper member 600.
Second Embodiment
[0102] A second embodiment is different from the first embodiment
in the shape of a stopper member 700. The following description
will focus on the difference from the first embodiment.
[0103] FIGS. 12A and 12B are cross-sectional views of the motor
operated valve 100 in a case where the stopper member 700 according
to the second embodiment is used in the motor operated valve 100.
FIG. 12A illustrates a valve closed state, and FIG. 12B illustrates
a fully open state.
[0104] A recess 337 is formed on the outer surface of the open end
of the rotation shaft 326. The stopper member 700 is fitted into
the recess 337, to be fitted to the open end of the rotation shaft
326. Details of the structure of the stopper member 700 will be
described later.
[0105] In the valve closed state, the projection 327 is stopped by
the second projection 252 in the rotating direction of the rotation
shaft 326. This structure restricts the movement of the rotation
shaft 326 in the valve closing direction (downward). In the fully
open state, a sticking out portion 706 (which will be described
later) of the stopper member 700 and the first projection 250 are
in contact with each other in the rotating direction of the
rotation shaft 326. This structure restricts the movement of the
rotation shaft 326 in the valve opening direction (upward).
[0106] FIGS. 13A to 13C are external views of the stopper member
700. FIG. 13A is a side view, FIG. 13B is a perspective view, and
FIG. 13C is a plan view.
[0107] The stopper member 700 includes fitting portions 702a, 702b,
and 702c (collectively referred to as "fitting portions 702")
having a rectangular plate shape, a connecting portion 704 having a
disc plate shape, and the sticking out portion 706 having a
rectangular plate shape. The fitting portions 702 each have a
plate-like fitting end portion 708, and a plate-like bridge portion
710. The fitting end portions 708 are arranged in parallel with the
connecting portion 704. The bridge portions 710 bridge between the
fitting end portions 708 and the inner surface of the connecting
portion 704 to connect the fitting end portions 708 with the
connecting portion 704. The fitting portions 702 extend from the
inner surface of the connecting portion 704 in the directions
toward the center of the inscribed circle of the connecting portion
704. Three fitting portions 702 are arranged in the circumferential
direction at intervals of 120 degrees. The connecting portion 704
connects the fitting portions 702 with the sticking out portion
706. The sticking out portion 706 includes a plate-like stopper
portion 712 and a plate-like bridge portion 714. The stopper
portion 712 is arranged in parallel with the connecting portion
704. The bridge portion 714 bridges between the stopper portion 712
and the inner surface of the connecting portion 704. The height of
the stopper portion 712 with respect to the connecting portion 704
is higher than that of the fitting end portion 708 with respect to
the connecting portion 704. The sticking out portion 706 extends
from the inner surface of the connecting portion 704 in a direction
toward the center of the inscribed circle of the connecting portion
704. The sticking out portion 706 is positioned at 180 degrees from
the fitting portion 702b.
[0108] FIGS. 14A and 14B are perspective views of the vicinity of
the stopper member 700 in a case where the stopper member 700 is
used in the motor operated valve 100. FIG. 14A illustrates a valve
closed state, and FIG. 14B illustrates a fully open state.
[0109] FIGS. 15A and 15B are transverse sectional views of the
vicinity of the stopper member 700 in a state in which the stopper
mechanism functions as viewed from below. FIG. 15A illustrates the
valve closed state, and FIG. 15B illustrates the fully open
state.
[0110] As illustrated in FIGS. 14A and 15A, in the valve closed
state, the projection 327 is sandwiched between the second
projection 252 and the sticking out portion 706. Specifically, the
projection 327 (stopping portion; second stopper portion 800) is
stopped by the stopping face (second stopping face 810) of the
second projection 252 in the rotating direction of the rotation
shaft 326. This structure restricts the movement of the rotation
shaft 326 in the valve closing direction. In addition, as
illustrated in FIGS. 14B and 15B, in the fully open state, the
sticking out portion 706 is sandwiched between the first projection
250 and the projection 327 (holding portion). Specifically, the
sticking out portion 706 (first stopper portion 820) is stopped by
the stopping face (first stopping face 830) of the first projection
250 in the rotating direction of the rotation shaft 326. This
structure restricts the movement of the rotation shaft 326 in the
valve opening direction.
[0111] As illustrated in FIGS. 15A and 15B, in the stopper member
700, the fitting portion 702b and the sticking out portion 706 are
arranged at intervals of 180 degrees. As a result, even when a
force acts on the sticking out portion 706 in the direction in
which the sticking out portion 706 fall off the rotation shaft 326
in the fully open state, the fitting portion 702b is pressed
against the rotation shaft 326. Thus, the stopper member 700 is
prevented from falling off the rotation shaft 326.
Third Embodiment
[0112] A third embodiment is different from the first embodiment in
the structure of the rotation shaft 326. The following description
will focus on the difference from the first embodiment.
[0113] FIGS. 16A and 16B are cross-sectional views of the vicinity
of the stopper member 500 of the motor operated valve 100 according
to the third embodiment. FIG. 16A illustrates a valve closed state,
and FIG. 16B illustrates a fully open state.
[0114] FIGS. 17A to 17E illustrate processes of operation of
assembling the rotation shaft 326 and the guiding member 242. FIGS.
17A to 17E are transverse sectional views of the vicinity of the
stopper member 500 as viewed from below illustrating the operation
processes in time sequence. A solid arrow in FIGS. 17A to 17E
indicates the rotating direction of the rotation shaft 326 during
assembly. A broken line arrow indicates the moving direction of the
stopper member 500.
[0115] As illustrated in FIGS. 16A and 16B, in the third
embodiment, an enlarged-diameter portion 335 of the rotation shaft
326 is larger in diameter than the enlarged-diameter portion 334 in
the first embodiment. The assembly of the rotation shaft 326 and
the guiding member 242 in the third embodiment is performed after
the stopper member 500 is fitted to the rotation shaft 326 in
advance. In this assembly, it is necessary to avoid interference
between the stopper member 500 and the external thread portion 244.
Thus, in the third embodiment, the enlarged-diameter portion 335
has a larger diameter so that the stopper member 500 will not touch
the external thread portion 244.
[0116] As illustrated in FIGS. 17A to 17E, a sloped portion 254 is
formed on a face of the first projection 250 opposite to the
stopping face (first stopping face 830) coming in contact with the
sticking out portion 506 (first stopper portion 820). The sloped
portion 254 makes the outer surface of the guiding member 242 and
the circumferential edge of the first projection 250 continuous
with each other. The sloped portion 254 is used in assembling the
rotation shaft 326 and the guiding member 242 in the third
embodiment. Hereinafter, this assembly will be explained with
reference to FIGS. 17A to 17E.
[0117] The stopper member 500 is mounted in advance on the rotation
shaft 326. First, the rotation shaft 326 is mounted around the
guiding member 242 until the lower end of the rotation shaft 326
(see FIG. 1) reaches the position of the first projection 250 (FIG.
17A). During the mounting, the protrusion 508 comes in contact with
the sloped portion 254 (FIG. 17B). As the rotation shaft 326 is
further advanced around the guiding member 242 after the protrusion
508 has come in contact with the sloped portion 254, the sticking
out portion 506 comes onto the outer surface of the first
projection 250 along the sloped portion 254 (FIG. 17C). As the
rotation shaft 326 is further advanced, the sticking out portion
506 passes over the first projection 250 (FIG. 17D). Finally, the
rotation shaft 326 and the stopper member 500 are turned in the
direction opposite to the direction in which the rotation shaft 326
is mounted around the guiding member 242, and the projection 327
and the sticking out portion 506 come into contact with each other
in the turning direction. The sticking out portion 506 is held
between the projection 327 (holding portion) and the first
projection 250 (FIG. 17E).
[0118] As described in relation to FIG. 4, in the first embodiment,
the stopper member 500 is mounted after the rotation shaft 326 and
the guiding member 242 are assembled. In the third embodiment,
because the sloped portion 254 is formed, the rotation shaft 326
and the guiding member 242 can be assembled with the stopper member
500 mounted on the rotation shaft 326 in advance. Thus, the
efficiency of assembly of the motor operated valve 100 is
improved.
Fourth Embodiment
[0119] A fourth embodiment is different from the first embodiment
in the position of a second projection 350. The following
description will focus on the difference from the first
embodiment.
[0120] FIGS. 18A and 18B are cross-sectional views of the vicinity
of the stopper member 500 of the motor operated valve 100 according
to the fourth embodiment. FIG. 18A illustrates a valve closed
state, and FIG. 18B illustrates a fully open state.
[0121] In the fourth embodiment, the base end of the
enlarged-diameter portion 334 is a stepped projection. In the
fourth embodiment, the sticking out portion 506 corresponds to a
first projection 348, and the projection at the base end of the
enlarged-diameter portion 334 corresponds to the second projection
350. As illustrated in FIG. 18A, in the valve closed state, the
second projection 350 (second stopper portion 800) and the stopping
face (second stopping face 810) of the first projection 250 of the
guiding member 242 are in contact with each other in the rotating
direction of a rotation shaft 325. Thus, during the valve closing
operation, the translational movement of the rotation shaft 325 in
the valve closing direction is restricted. In addition, as
illustrated in FIG. 18B, in the fully open state, the first
projection 348 (first stopper portion 820) and the stopping face
(first stopping face 830) of the first projection 250 of the
guiding member 242 are in contact with each other in the rotating
direction. Thus, during the valve opening operation, the
translational movement of the rotation shaft 325 in the valve
opening direction is restricted. This structure enables appropriate
restriction of the translational movement of the rotation shaft
325.
Fifth Embodiment
[0122] A fifth embodiment is different from the first embodiment in
that the stopper member 500 is not provided. The following
description will be focused on the difference from the first
embodiment.
[0123] FIGS. 19A to 19C are partially-enlarged cross-sectional
views of the vicinity of a stopper mechanism of the motor operated
valve 100 according to the fifth embodiment. FIG. 19A illustrates a
valve operating state, FIG. 19B illustrates a valve closed state,
and FIG. 19C illustrates a valve open state.
[0124] In the fifth embodiment, part of the open end portion of a
rotation shaft 352 sticks out in the axial direction to constitute
a stopper portion 840. The stopper portion 840 serves as both of
the first stopper portion and the second stopper portion. The
stopper portion 840 is formed by bending the sticking out portion
at the open end portion of the rotation shaft 352. The formation of
the stopper portion 840 will be described later in detail.
[0125] In the valve closed state, one end face of the stopper
portion 840 in the rotating direction is stopped by the stopping
face (second stopping face 810) of the second projection 252. This
structure restricts the movement of the rotation shaft 352 in the
valve closing direction (downward). In addition, in the fully open
state, the other end face of the stopper portion 840 in the
rotating direction is stopped by the stopping face (first stopping
face 830) of the first projection 250. This structure restricts the
movement of the rotation shaft 352 in the valve opening direction
(upward).
[0126] FIGS. 20A to 20C are conceptual diagram illustrating
processes of formation of the stopper portion 840. All of FIGS. 20A
to 20C illustrate states before the can 302 is mounted on the
second body 240. FIG. 20A illustrates a state in which the external
thread portion 244 and the internal thread portion 328 are started
to be engaged with each other, FIG. 20B illustrates a state before
the stopper portion 840 is machined, and FIG. 20C illustrates a
state after the stopper portion 840 is machined. An arrow
illustrated in FIGS. 20B and 20C indicates the direction in which a
tool 900 is inserted.
[0127] First, the external thread portion 244 and the internal
thread portion 328 are engaged with each other, so that the
rotation shaft 352 is mounted on the guiding member 242. As
illustrated in FIG. 20B, after a sticking out portion 354 at the
open end portion of the rotation shaft 352 is brought to a position
at a height between the first projection 250 and the second
projection 252 in the axial direction, the tool 900 is inserted
between the rotor 320 and the second body 240. The tool 900 is
brought in contact with the lower end portion of the sticking out
portion 354, and the tool 900 is then pressed in the radial
direction of the rotation shaft 352 to bend the sticking out
portion 354 (FIG. 20C). The bent sticking out portion 354
constitutes the stopper portion 840. The stopper portion 840 can
also be referred to as a "bent portion" at the open end portion of
the rotation shaft 352.
[0128] In the fifth embodiment, the bent portion at the open end
portion of the rotation shaft 352 constitutes the stopper portion
840. This structure eliminates the need of the stopper member,
which reduces the number of components of the motor operated valve
100. In addition, because the stopper portion 840 is formed
integrally with the rotation shaft 352, the position of the stopper
portion 840 on the rotation shaft 352 can be easily managed.
[0129] In the fifth embodiment as well, the first stopping face 830
and the second stopping face 810 are located between the screwed
portion and the valve section 202. In addition, the screwed portion
of the feed screw mechanism and the rotor 320 are located at the
same height in the axial direction. Thus, the distance between the
center of gravity and the support point of the rotor 320 can be
made shorter, and whirling of the rotor 320 due to the rotation of
the rotor 320 is suppressed.
[0130] In the fifth embodiment as well, the first projection 250
(first stopping face 830) is located inside the enlarged-diameter
portion 334 depending on the position of the rotor 320 in the
translation direction (the driving state of the rotor 320).
Specifically, because the first stopping face 830 is present under
the rotation shaft 352 of the rotor 320, the total length of the
rotor 320, the first stopper mechanism, and the second stopper
mechanism in the axial direction can be made shorter. Thus, the
length of the motor operated valve 100 in the axial direction can
be made shorter.
[0131] The embodiments of the present invention has been described
above. The present invention is not limited to the embodiments and
it will be obvious to those skilled in the art that various
modifications could be further developed within the technical idea
underlying the present invention.
[0132] In the first to fourth embodiments described above, a
stepped portion is formed at the lower end of the rotation shaft.
In a modification, any structure in which the sticking out portion
of the stopper member can be formed radially inward from the inner
surface of the rotation shaft may be used. For example, a hole into
which the sticking out portion is inserted may be formed near the
open end of the rotation shaft. Alternatively, a hole may be formed
at another portion of the rotation shaft depending on the position
of the stopper member in the axial direction.
[0133] In the first to fourth embodiments described above, the
projection and the second projection come into contact with each
other to restrict the translational movement of the rotation shaft.
In a modification, a portion at the open end of the rotation shaft
other than the projection may come into contact with the second
projection in the rotating direction of the rotor. In this case as
well, the movement of the rotation shaft in the axial direction can
be restricted.
[0134] In the first to fourth embodiments described above, the
protrusion is sandwiched between the projection and the guiding
member in the radial direction. In a modification, the protrusion
may be inserted between a portion at the open end of the rotation
shaft other than projection and the guiding member. In this case as
well, the stopper member is prevented from falling off the rotation
shaft.
[0135] In the fifth embodiment described above, the stopper portion
840 serves as both of the first stopper portion and the second
stopper portion. In a modification, two stopper portions may be
formed. Specifically, two portions (sticking out portions)
protruding from the open end of the rotation shaft in the axial
direction may be formed at positions away from each other, and
bent. One of the bent portions (stopper portions) of the sticking
out portions may be the first stopper portion, and the other may be
the second stopper portion. In this manner, the functions of the
stopper portion 840 may be separated into the function during
upward movement of the rotation shaft and that during downward
movement thereof.
[0136] In the embodiments described above, the motor operated valve
in which the valve element touches and leaves the valve seat and
the valve section is completely closed in the valve closed state
has been described. In a modification, a valve element may be moved
into and out of a valve hole like a so-called spool valve, and a
slight leakage of fluid may be permitted in the valve closed
state.
[0137] While the motor operated valve is a motor operated expansion
valve in the embodiment described above, the motor operated valve
may be an on-off valve or a flow control valve without an expanding
function.
[0138] In the embodiments described above, the structure in which
the valve element and the shaft are integrally formed has been
described. In a modification, the structure is not limited thereto,
and the valve element and the shaft may be separate members that
can move integrally. In this case, the valve element and the shaft
may be structurally integrated. Alternatively, the valve element
and the shaft may be integrally movable, and also movable relative
to each other. For example, the valve element and the shaft may be
integrally movable while the valve is being opened, and may be
movable relative to each other during valve closing operation, like
the motor operated valve described in Japanese Patent Application
Publication No. 2016-205584.
[0139] In the embodiments described above, the first projection is
integrally formed with the guiding member. In a modification, the
first projection and the guiding member may be separate members
that are integrally fixed.
[0140] In the embodiments described above, the notch 253 is formed
after machining of the external thread portion 244, and the notch
301 is formed before machining of the internal thread portion 328.
In a modification, the notch 253 may be formed before machining of
the external thread portion 244, and the notch 301 may be formed
after machining of the internal thread portion 328. In any case,
the tool used for machining of the external thread portion or the
internal thread portion is used, and the movement of the working
tool and the rotation of the machined member are maintained to form
the notches. As a result, the distance L1 and the distance L2 can
be set to integer multiples of the pitch P.
[0141] In the embodiments described above, the structure in which
the notches are formed on the projection of the rotation shaft and
the second projection of the guiding member has been described. In
a modification, the notches may be formed on other portions such as
at a position, away from the stopper portion, on the
enlarged-diameter portion of the rotation shaft or at a position,
away from the stopping face, of the large-diameter portion of the
guiding member.
[0142] In the embodiments described above, the cross-section in
which the distance L1 is defined is present on a plane including
the second stopping face 810 (intersection 253a) and the axis C1.
In a modification, the cross-section may be on a plane including
another position of the notch 253 and the axis C1. In addition, in
the embodiments described above, the cross-section in which the
distance L2 is defined is present on a plane including the second
stopper portion 800 (intersection 301a) and the axis C2. In a
modification, the cross-section may be on a plane including another
position of the notch 301 and the axis C2.
[0143] In the embodiments described above, the distance L1 and the
distance L2 are set to integer multiples of the pitch P. In a
modification, the distance L1 and the distance L2 may be integer
multiples of 1/2 of the pitch (1/2P) based on the roots and the
crests of the thread portions. In this case as well, the design of
the rotation shaft and the guiding member so that the contact face
and the second stopping face come in contact with each other can be
made simpler by determining the distance between the notches and
the roots of the thread portions.
[0144] In the embodiments described above, the structure in which
the rotor and the stator have an equal length in the axial
direction has been described. In a modification, the rotor and the
stator may have different length, such as the stator is longer than
the rotor in the axial direction. In this case as well, the thrust
for lifting the valve element in the valve opening direction from
the valve closed state can be increased by setting the relative
positions of the rotor and the stator so that the area in which the
rotor and the stator face each other is maximum when the valve is
closed.
[0145] In the embodiments described above, the structure in which
the stopper portion is stopped in the rotating direction by the
first projection or the second projection has been described. In a
modification, the stopper portion and the stopping face may be
brought into contact in the axial direction of the rotor. For
example, in the first embodiment (FIGS. 5A to 5D), the first
stopper mechanism may be such that the upper face of the sticking
out portion 506 is stopped by the lower face of the first
projection 250. In addition, the second stopper mechanism may be
such that the lower face of the sticking out portion 506 is stopped
by the upper face of the second projection 252. The relative
position of the sticking out portion 506 in the stopper member 500
may be set so that such a stopper structure is achieved. In
addition, in the fifth embodiment (FIGS. 19A to 19C), the stopper
portion 840 may be bent at a right angle with respect to the inner
surface of the rotation shaft 352, and the upper face and the lower
face of the stopper portion 840 may be stopped by the first
projection 250 and the second projection 252, respectively. The
same applies to the second to fourth embodiments.
[0146] In the embodiments described above, the structure in which
the first body 220, the second body 240, and the third body 260
constitute the body of the motor operated valve, and the motor unit
300 is fixed to these three bodies has been presented as an example
of the motor operated valve. In a modification, a structure in
which the second body 240 and the third body 260 constitute the
body (valve body) of the motor operated valve, and the motor unit
300 is fixed to the second body 240 and the third body 260 may be a
"motor operated valve". In this case, the first body 220
constitutes a "piping body".
[0147] The present invention is not limited to the above-described
embodiments and modifications only, and the components may be
further modified to arrive at various other embodiments without
departing from the scope of the invention. Various other
embodiments may be further formed by combining, as appropriate, a
plurality of structural components disclosed in the above-described
embodiments and modifications. Furthermore, one or some of all of
the components exemplified in the above-described embodiments and
modifications may be left unused or removed.
* * * * *